RETIREMENT · FIRE

Coast FIRE Calculator

Find your Coast FIRE number — the amount you need saved today so that compound growth alone reaches your retirement target without any additional contributions.

LAST REVIEWED · APR 08, 2026 · BY A. CHEN, CFP®
You need
$140,494
Coast FIRE DetailsReset
Current age
30 yrs
1860
Target retirement age
65 yrs
5075
Current savings
$80,000
$0$2M
Retirement target25x annual spending
$1,500,000
$250K$5M
Expected returnAnnual, nominal
7%
3%12%
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How Coast FIRE works

Coast FIRE is the point where your existing savings, if left untouched, will grow to your retirement target by your target age through compound returns alone. Once you’ve ‘coasted,’ you only need to earn enough to cover current expenses — no more saving for retirement.

Why Coast FIRE is appealing

It gives you optionality. You can switch to a lower-paying job you love, go part-time, start a business, or take a sabbatical — all without jeopardizing your long-term retirement plan.

Coast FIRE vs regular FIRE

Regular FIRE means you can stop working entirely. Coast FIRE means you can stop saving but still need income for current expenses. It’s a more achievable milestone that many people reach in their 30s or 40s.

Methodology. Coast Number = Target Amount × (1 + return rate)^(-years to target). If current savings exceed the coast number, you are already ‘coasting.’ Years until coast calculated by solving for n in: currentSavings × (1+r)^n = coastNumber.

Sources

  • Coast FIRE concept — derived from standard present value formula
  • Historical equity returns: ~7% nominal (Ibbotson SBBI)
  • Standard FIRE target: 25× annual spending (4% safe withdrawal rate)
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Frequently asked questions

What return rate should I use? +
7% nominal is standard for a stock-heavy portfolio. Use 5% for a more conservative estimate. The rate matters enormously — a 1% difference in return changes the coast number by 20–30% over 30 years.
Does Coast FIRE account for inflation? +
Not directly. If you use a 7% nominal return, your target amount should be in future dollars. For today’s dollars, use a 4–5% real return and a target in current purchasing power.
Can I hit Coast FIRE even with a modest salary? +
Yes — especially if you start early. Someone saving $500/month from age 22 can reach a Coast FIRE number for a $1M target by their early 30s, assuming 7% returns.
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